Problem: Which of the following numbers is a multiple of 4? ${55,57,69,90,112}$
Answer: The multiples of $4$ are $4$ $8$ $12$ $16$ ..... In general, any number that leaves no remainder when divided by $4$ is considered a multiple of $4$ We can start by dividing each of our answer choices by $4$ $55 \div 4 = 13\text{ R }3$ $57 \div 4 = 14\text{ R }1$ $69 \div 4 = 17\text{ R }1$ $90 \div 4 = 22\text{ R }2$ $112 \div 4 = 28$ The only answer choice that leaves no remainder after the division is $112$ $ 28$ $4$ $112$ We can check our answer by looking at the prime factorization of both numbers. Notice that the prime factors of $4$ are contained within the prime factors of $112$ $112 = 2\times2\times2\times2\times7 4 = 2\times2$ Therefore the only multiple of $4$ out of our choices is $112$. We can say that $112$ is divisible by $4$.